<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>设置一个简单的cookie</title>

    
        <script>
        function getCookie(c_name) {
            if (document.cookie.length > 0) {
                c_start = document.cookie.indexOf(c_name + "=")
                if (c_start != -1) {
                    c_start = c_start + c_name.length + 1
                    c_end = document.cookie.indexOf(";", c_start)
                    if (c_end == -1) c_end = document.cookie.length
                    return unescape(document.cookie.substring(c_start, c_end))
                }
            }
            return ""
        }

        function setCookie(c_name, value, expiredays) {
            var exdate = new Date()
            exdate.setDate(exdate.getDate() + expiredays)
            document.cookie = c_name + "=" + escape(value) +
                ((expiredays == null) ? "" : "; expires=" + exdate.toGMTString())
        }

        function checkCookie() {
            username = getCookie('username')
            if (username != null && username != "")
            { alert('Welcome again ' + username + '!') }
            else {
                username = prompt('Please enter your name:', "")
                if (username != null && username != "") {
                    setCookie('username', username, 365)
                }
            }
        }

        checkCookie()
    </script>
</head>
<body>
    <h1>设置cookie</h1>
</body>
</html>